What is a recomp?
Three ways people bring old software to new machines, and why the difference matters.
What is a recomp?
A static recompilation ("recomp") translates a program's compiled machine code, instruction by instruction, into C or C++ ahead of time, then compiles that for a modern machine. The result is a native port without an emulator at run time. N64: Recompiled (behind Zelda 64: Recompiled) and XenonRecomp (behind Unleashed Recompiled) are the best-known recompilers.
What is a decomp?
A decompilation ("decomp") is the slow, mostly human job of writing readable C that compiles back into the original binary. A matching decomp produces a byte-for-byte identical executable, which proves the source is faithful. Projects like the Super Mario 64 and Ocarina of Time decomps took years.
How are they different?
A recomp is fast and mostly automatic, but the output is machine-shaped code that is hard to read or change deeply. A decomp is slow but gives real, understandable source that people can port, fix and mod freely. Many projects combine both: a recomp to ship sooner, a decomp to understand the game.
What is a clean-room reimplementation?
A program rewritten from scratch by people working from documentation and observed behaviour, not from the original code. ReactOS, Wine and VectorCraft (an Illustrator-style editor) work this way, and so do engine rewrites like OpenMW.
Is any of this legal?
The projects listed here distribute their own code and tools, never the original game or program data. To play most of them you supply a copy you own. The few builds playable on this site either regenerate all assets themselves, or use data that is freely licensed, and each says which.
What do the labels mean?
Every entry carries a provenance label (human-led, AI-assisted, AI-generated, or not stated), taken from what the project itself says. See the about page for the rules.